An extremely rare, benign or malignant germ cell tumor characterized, clinically, by a teratoma presenting in an extragonadal location (for example retroperitoneum, mediastinum, craniofacial or sacrococcygeal region, intraosseous, solid organs) and histologically by displaying well-differentiated structures as well as immature elements. Presenting symptoms are variable depending on size and location of tumor. [from
SNOMEDCT_US]